Patching Large Gaps (Porsche 928 Project)

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PostPosted: Mon Sep 26, 2016 1:29 pm
Hey guys! I'm doing my very first welding job with two Porsche 928's I bought for cheap (with one as a donor). The car was hit in the rear, and left to rust.

Long story short, I did a terrible job of cutting the proper shaped panel and made it too small. As a result I have some gaps (at least 1 inch) between the panel and the body, that I have to somehow connect. What would be the best way to do this? (928 bodies aren't the cheapest to come by, so I have to make do with what I have now).

The car metal is 14 gauge. I have some 16 gauge sheet metal that I was simply going to cut into strips and weld into the gaps to kinda patch it. Is it a bad idea to use different gauges? Is sheet metal, even the correct gauge, adequate material?

Also, what tools do you/would you have used to cut the metal in this case, and what process would you have used? I used a very unintelligent process at first, but even if I had used the bumper as a guide originally, I feel like a Dykem marker and grinder cutting wheel still wouldn't have given me the results I wanted, especially with the irregular shape of metal near the bumper.

If I could go back in time, I would have taken my sweet time with the prep work. Now I'm just trying to get through the project without butchering the car any further. Considering this is my first time welding too, the odds are definitely stacked against me! Any advice would be greatly appreciated. Thanks!
Attachments
IMG_20160707_112005.jpg
Before rusted metal was cut
IMG_20160915_100223.jpg
After rusted metal was cut
IMG_20160926_142129.jpg
Large gap



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PostPosted: Mon Sep 26, 2016 3:20 pm
I am a newb like you and still learning. I am having trouble cutting patches myself and have made many mistakes. Fortunately, I am fixing some rust on a inner wheel well before spot welding in my quarter.

I just posted up about how to fix small blow through areas--which have been a challenge for me. You are going to have to butt weld a new piece of metal (ideally the same thickness of the quarter) where that large gap is.

Some of the Eastwood videos prompt you to spot weld backer strips under the panels and then spot weld your patch to that. A lot of people will say that is troublesome because it could lead to rust. Seems to me it would be easier for the newb and you could abate some of the potential rust if you primed first.

Good luck with your project.



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PostPosted: Fri Nov 11, 2016 2:06 pm
928Vette wrote:Long story short, I did a terrible job of cutting the proper shaped panel and made it too small. As a result I have some gaps (at least 1 inch) between the panel and the body, that I have to somehow connect. What would be the best way to do this?

Also, what tools do you/would you have used to cut the metal

If I could go back in time, I would have taken my sweet time with the prep work. Now I'm just trying to get through the project without butchering the car any further. Considering this is my first time welding too, the odds are definitely stacked against me! Any advice would be greatly appreciated. Thanks!


This has been up for a while now with no posts BUT WOW! :rolleyes:

1st Off Always Measure Twice! three times even sometimes four times! before cutting!
Its always easier to cut more off than add to it later, and ALWAYS take your Sweet time with Prep work ALWAYS!

The time to realize your in over your head is not when your in the middle of a job :flatten:

I use a small air powered reciprocating saw for cutting body panels see this thread
viewtopic.php?f=6&t=25854
i also use Tin Snips and Die Grinders with very thin metal Cutting wheels.

Learning how to weld Sheet metal on a 928 project is not the time to be learning this is when you should be showing off your Skills.

Ya the Damage is done If you try to patch it up with 1 inch patches its gonna look like Fidos Butt! The best thing to do is Buy another Quarter panel.

pointers
http://www.metalmeet.com/forum/index.php
There are many more on line

Dang they want dang near 3k for a quarter panel for that thing wow
Here is an option for you though
http://cars.forumsee.com/a/m/s/p12-1670 ... e-928.html
If it were mine I would be Glassing a new quarter panel on it! Its fast and easy to deal with
Last edited by Doright on Fri Nov 11, 2016 8:22 pm, edited 1 time in total.
Dennis B.
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PostPosted: Fri Nov 11, 2016 7:53 pm
You have enough room to weld a decent patch in there.
What Dennis said about learning on a Porsche 928 is certainly true but you are in it now so let's try to salvage that quarter.

Match sure you have the correct gauge metal on hand. Practice on a couple of small pieces until you are confident you have the welder dialed in. I like to use .023" wire (I use a MIG with gas) on sheet metal and you need to learn how to spot weld so that you get good penetration with a quick pull and release of the trigger. My welder actually has a spot weld setting so I can set the time. This allows me to pull the trigger full open and the welder will do a quick spot and stop until I release and pull the trigger again.

When you have your quarter in the perfect position, cut your patch to extend 1/4 - 1/2" beyond the hole in all directions. Lay the patch on the panel and scribe your cut line. You want as tight a fit as you can get without flexing the metal.

Hold the patch in place with magnets and then place a spot weld at each corner and about 3" apart down the seams. Take your time and be sure the edges of the metal line up with each other. You will need to let the welds cool before the next round so using a hammer and dolly, planish the spot welds.
Continue the process of spot welding by tacking another spot on to each of the previous ones, planish, etc.

Chevman wrote a great post on metal working that appears at the top of this forum. You can learn a lot by reading it.
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